Redesignability analysis of digital VLSI circuits with incomplete implementation information

This paper describes a new problem of digital circuit design-redesign of digital VLSI circuits with incomplete implementation information-and presents a solution-redesign process. Efficient algorithms are developed to derive the transfer functions of the portion with incomplete implementation information. Thus, the portion can be reimplemented using the derived transfer functions. We do not intend to discover the exact circuit schematic and components that were present in the circuit originally implemented. Rather, the functions originally intended to be present will be identical. A set of simple rules is proposed in this study to quickly analyze the redesignability of a target circuit.